Packing structures for well devices



May 7, 1957 E. H. CLARK, JR 2,791,278

PACKING STRUCTURES ECE WELL DEVICES Filed Aug. 16, 1954 2 Sheets-Sheet 1H6. l. c?. I; 3.

NVENT Mez/w au( 74A/Www TrQEAMU/S May 7, 1957 E. H. CLARK, JR 2,791,278

PACKING STRUCTURES FCR WELL DEVICES Filed Aug. 16, 1954 2 Sheets-#Sheet2 Ho. 4. I.; 5.

BY www )m .4free/v5 VS l PACKING STRUCTURES FOR WELL DEVICES Earnest H.Clark, Jr., Downey, Calif., assigner to Baker 011 Tools, Inc., LosAngeles, Calif., a corporation of California Application August 16,1954, Serial No. 449,944

13 Claims. (CIL 1661-204) The present invention relates to packingstructures, and

more particularly to packing; structures incorporated inv subsurfacewell devices which'y are. subjected to high pressures or hightemperatures, or to both high pressures and temperatures.

Subsurface well` tools include natural or synthetic rubber packingelements for effecting a seal within a string of well casing, or similarwell conduit. Although an eiiicient seal is provided/the rubber materialtends to cold flow through adjacent clearance spaces existing. betweenthe well tool and casing, or betweenv parts of the well tool itself,particularly when the tool, is subjected to high pressures or hightemperatures, or the combination of high pressures and hightemperatures. If suicient rubber flows through such clearance spaces,the packing fails,

lt has been proposed to minimize the aforenoted didiculty by backingV upthe rubber packing withl rings of lead or similar pliant, inelasticmaterial, which willV be moved .into bridging position across theclearance space or spaces, and thereby prevent the rubber material fromcold flowing thereinto. The use of such` back-up rings ishighlyeffective, but under extreme conditions of high pressures andtemperatures, they, in turn, may be forced intoV the clearance spaces tothe extent wherefailure of the packing' structure occurs.

It is, accordingly, an object of the present invention to provide apacking structure which can withstand extremely high pressures andtemperatures, of the order encountered in well bores.

Another object of the invention is to provide a relatively simple andinexpensive device for preventing rubber and other packing materialsfrom cold flowing into clearance spaces between a well tool andV wellconduit when subjected to very high pressures and temperatures, of theorder present in certain Well bores.

This invention possesses many other advantages,l and has other objectswhich may be made more clearly apparent from a consideration of a forminwbich it may be embodied. Such formis shown in the drawingsaccompanying and forming part of the present specification. It will nowbe described in detail, for the purpose of illustrating` the generalprinciples of the invent-ion; butit is to be understood that suchdetailed description is. not to be. taken in a limiting sense, since thescope of the invention. is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal sectional view of a well packer embodying theinvention, with its 4parts in retracted posi,- tion for lowering in awell casing;

Fig. 2 is a view similar to Fig. l, with portions of the packer expandedagainst' the well casing;

Fig. 3 is a view similar to Fig. i, disclosing, the packer anchored inpacked-oil condition` within the well casing;

Fig. 4 is an enlarged` fragmentary longitudinal sectionthrough a portionof the Well packer shownin Fig. l;

Fig. 5 is a fragmentary longitudinal section through a portion of thewell packer, as disclosedin Fig. 3.

A well packer A is disclosed in Fig. 1 as being coupled` States PatentrO ICC to the end of' a string of tubing B, or the like, with parts ofthe well4 packer in retracted position to permit its freedom of movementdownwardly through a casing C to the' desired setting point. The packerincludes a main body 10 carrying a set of upper 'segmental slips 11disposed adjacent a transverse abutment 12 secured on the upper end ofthe body, and adapted to be moved into engagement with the casing CV byan upper frusto-conical expander 13 initially retained in retractedposition by one or more shear screws 14 attaching it to the main body.The upper slips 11 are similarly lretained in retracted position byrespective shearscrews 15,16 'securing them to the expander 13 and body10.` A lower setof segmental slips 17 is held initially in retractedposition and attachedk to the main body 10 by shear screws 18k and to alower frusto-conical expander 19 through another set of shear screws 20,this lattery expander being held initially in ineffective position bysuitable shear screws 21 attaching it to the body. The upperA sets ofscrews 1d, 1S, 16 have a lower shear value than the lower sets 1S, Ztl,21, to permit prior outward expansion of the upper. set of slips 11 intoanchoring engagement with the well casing C.

A packing structure 22' is positioned between and suitablyv associatedwith the confronting portions of the frustoconical expanders 13; 19.This packing structure includes a packing sleeve 23 of synthetic ornatural rubber initially disposed in retracted position. The sleeve 23is provided `with a central portion 24 adapted to be expanded outwardlyinto sealingl engagement with the wall of the Iwel-l casing C and withreduced diameter, generally cylindrical end portions 25"', each of whichis disposed within an annular recess 26 in an expander. T he outersurface 27 of. the cylindrical end portion engages the cylindrical innerwall 28 defining the recess, the terminal portion 29 of the packingsleeve engaging an end shoulder 30 detining the recess. The innersurface 31 of the packing 23 engages the periphery of the body 10', theend portions 25 of' the packing sleeve being provided with annular lipseals 32 facing toward one another and Isealingly engaging the peripheryof the body 14)- to prevent leakage of fiuid from the interior of thepacking 23 to its exterior. Such fluid, as described hereinbelow, canpass from the inner central passage 33 inthe body, through one or morelateral ports 34 in the body, to the interior of the packing 23.

A valve assembly housing 35 is threadedly secured to the lower end ofthe packer body 10. T hishousing contains a tripping ball seat 36initially secured to it by a shear screw 37.- The seat has an upstandingarm 38 integral therewith initially engaging a buoyant back pressureball valve element 39 to hold. it in ineffective position against theinterior of the housing and thereby prevent its upward movement intoseating engagement with a valve seat 401 provided at the lower end ofthe main body 1t) and surrounding the central passage 33 through thebody. Removal of the retaining arm 38 will permit the ball 39 to moveupwardly into engagement w-ith its companion valve seat 40, wheneverupward or reverse flow of fluid throughthe body passage 33 tends tooccur.

The packer A is run into the casing C by means of the tubing string Battached to its body 19, to the desired setting point, and circulationis established therethrough to-remove any undesired foreign matter inthe well casing. Thereafter, atripping ball 41 is lowered or pumped downthrough the tubing 13 andthe body passage 33 into seating engagementwith the tripping ball seat 36, which permits the pressure of the fluidwithin the tubing string and the packer body tobe increased, this uidunder pressure passingV laterally outward through the ports 34 in thebody to the interior of the packing sleeve 23'. When sufiicient pressureis imposed* on the uid, it will inflate the packing sleeve outwardlyagainst the well casing, as disclosed in Fig. 2, and will then disruptthc upper sets of shear screws 14, 15, 16, sliding the upper expander 13in an upward direction along the body 10 to move the upper slips 11against the abutment 12 and then laterally outward into grippingengagement with the well casing C.

After the upper slips 13 have thus been anchored in the well casing, thepressure of the fluid in the tubing string B and the packer body 10 maybe increased to a further extent, to disrupt the shear screw 37 holdingthe tripping ball seat 36 to the valve housing 35 and eject this seat,together with its upstanding arm 38 entirely from the housing whichfrees the back pressure ball valve element 39 and allows it to moveupwardly into engagement with its companion seat 40, whenever reverseflow of fluid through the well packer tends to occur.

An upwardly directed pull or strain may now be taken on the tubingstring B and the packer body 10. Since the upper set of slips 11prevents the upper expander 13 from moving upwardly to any furtherextent, such upward strain or movement on the packer body will move thelower expander 19 and lower slips 17 toward the upper expander 13,foreshortening and compressing the packing sleeve 23 and expanding itoutwardly into firm seal-v ing engagement with the wall of the wellcasing C and the exterior of the main body 10. A continuation of theupward strain will effect shearing of the screws 21, 18, 20, holding thelower expander 19 and slips 17 to the body 10 and the slips to theexpander, and will cause the lower portion of the body 10 and valvehousing 35 to engage the lower slips 17, sliding them upwardly along thelower expander 19 and radially outward into anchoring engagement withthe wall of the well casing C. The various slips, expanders and packingsleeves are held in their respective expanded positions by an annularsplit ratchet ring 42 contained within a groove 43 in the upper expander13 and engaging downwardly facing circular ratchet teeth 44 formed onthe exterior of the body. The packer A is now fully anchored inpackedolf condition within the well casing C, as disclosed in Fig. 3.

Fluent substances under pressure may now be pumped down the tubingstring B and out through the well packer A to perform a desired functionin the well bore. As an example, cement slurry may be pumped under veryhigh pressure through the well packer and into a formation surroundingthe well casing C. When the well packer is subjected to comparativelyhigh pressures, which may be of the order of 7,000 or 8,000 p. s. i.,and is subjected to comparatively high temperatures encountered in thewell bore, such as 300 to 350 degrees F., the rubber packing materialmay tend to be displaced by such pressures through the annular clearancespaces 45 that exist between the expanders 13, 19 and the wall of thewell casing C and also through the clearance spaces between theexpanders and the packer body- 10 itself. The latter clearance spacesare relatively small in extent and may ordinarily be insufficient toallow any substantial cold owing of the rubber packing materialthereinto. However, the annular clearance spaces 45 between theexpanders 13, 19 and the wall of the well casing are substantial, andoffer a comparatively large area through which the rubber packingmaterial can be squeezed. In the specific form of the inventiondisclosed in the drawings, the rubber packing material is prevented fromcold owing into the larger annular clearance spaces 45 between theexpanders and the wall of the well casing, although it will be evidentthat the invention is useful in preventing cold flowing of the rubberpacking material through clearance spaces in general.

As specifically illustrated, each expander 13, 19 actually constitutes aretainer or abutment for the packing structure 22, since it tends toprevent endwise movement of the packing structure. The main intermediateportion 24 of the rubber packing sleeve 23 has an external diametersubstantially greater than the end cylindrical portions 25 of thepacking sleeve. There is an inclined frusto-conical surface 46 betweenthe exterior of each cylindrical portion 25 and the periphery of themain central portion 24 of the packing sleeve. This inclined surface 46is spaced longitudinally away from the confronting end 47, 4S of theexpander or abutment 13, 19, the packing sleeve defining an annularexternal groove 49 with the adjacent abutment, in which elements 50, S1are disposed for preventing cold flow of the rubber packing materialthrough the annular clearance space 45. Actually, the upper and lowerportions of 'the packing sleeve 23 and the adjacent expanders orabutments 13, 19 are alike, so that an explanation of one expander andone side of the packing structure will sutlice for both. It issutlicient to state 'that the ends of the packing sleeve and of theadjacent portions of the abutments are identical, being reverselydisposed.

Disposed within the groove 49 provided between the upper abutment 13 and'the packing sleeve 23 is an annulus 50 of pliant, inelastic material,such as lead, which has an inner cylindrical surface 52 embracing theperiphery of the cylindrical portion 25 of the packing sleeve, an outercylindrical surface 53 which is adapted to be moved outwardly intosealing engagement with the wall of the well casing C, and anintervening lower tapered or inclined surface 54 which is companion toand engages the corresponding inclined surface 46 on the packing sleeve23. The deformable annulus 50 is also provided with an upper inclinedsurface 55, which inclines in a downward and outward direction withrespect to the associated abutment 13, and this inclined surface engagesa companion internal inclined surface 56 on a generally frusto-conicalring 51, which is substantially thinner than 'the lead ring 50 and whichis made of -a malleable material, such as aluminum, malleable iron,wrought iron, mild steel, copper, brass or bronze.

The frusto-conical ring 51 has an upper end portion 57 tting within arecess 58 in the lower outer portion of the adjacent abutment 13, and italso has an outer inclined surface 59 which may be generally parallel tothe inner inclined surface 56, although not necessarily so, thatinitially tapers in a downward and laterally outward direction withrespect to an adjacent transverse shoulder 48 formed at the lowerportion of the upper expander, there being initially a substantial spacebetween the abutment shoulder 48 and the outer surface 59 of the thinmalleable ring. The outer surface of the ring 51, as well as the outersurface 55 of the lead ring 50 which it engages, are initially inretracted position, removed from engagement with the wall of the wellcasing C to essentially the same extent as the central sealing portion24 of the packing sleeve 23 itself.

It is to be noted that rubber packing material is disposed within thepliant, inelastic or lead ring 50 and that this lead ring is disposedwithin the malleable outer ring 51. This malleable outer ring 51 may bestretched and expanded in an outward direction with deformation, but itis not as readily deformable as the lead, or similar material, of whichthe pliant, inelastic ring 50 is formed. The outer ring 51 resistsdeformation to a far greater extent than the lead inner ring 50 and isadapted to bc stretched outwardly into engagement with the wall of thewell casing C, in order to bridge the annular clearance space 45 betweenthe abutment 13 and the casing, and prevent cold flowing of the innerlead ring 50 and the rubber packing 23 thereinto.

When an upward strain is taken on the tubing string B and the packerbody 10, for the purpose of foresholtening the packing sleeve 23 andexpanding it into sealing engagement with the wall of the well casing C,the upward force on the rubber will act through the inclined surfaces 54of the lead vpackingringsA 50 to stretch and expand the latter inanoutward direction'toward the well casing.A As

such stretching and expansion of each lead ring occurs, it acts upon thefrusto-conical ring l to tend to stretch and expand it in an outwarddirection, shifting it about its inner contact region 57 with theabutment 13 and stretching it outwardly so that the outer vring 51engages the abutment shoulder 48 and also the wall of the well casing C.The rubber packing material will stretch the lead sealing ring 50outwardly against the wall of the well casing before sufficientcompression is exerted on the packing sleeve 23 tending to cause it toHow around the ex terior of the lead seal ring. Similarly, the outermalleable ring S1 is expanded outwardly into its bridging positionacross the clearance space 45 between the abutment 13 and the wellcasing C before the lead sealing material is subjected to sufficientpressure as to cause it to flow around the exterior of the malleablering. Accordingly, the rubber packing 23 is prevented from moving aroundthe exterior of the lead ring 50, the latter also being prevented frommoving around the exterior of the malleable ring 51, which will insurethat the lead ring 50 will function to prevent cold ow ofthe rubbermember 23 past it and the malleable ring 51 will act to insure cold flowof the lead material 50 past it.

The lead ring is more ductile than the malleable ring and will beexpanded against the casing more readily 4by the rubber packing sleeve.If the lead ring 50 were omitted and the malleable ring 51 onlywere'used to back up the rubber packing material 23, its lesserductility, as compared to lead, might cause the rubber to flow around itbefore it was expanded outwardly into engagement with the well casing.Thus, the use of lead as an intervening material between the rubbersleeve 23 and the malleable outer ring 51 offers several advantages.panded against the casing by the rubber sleeve 23, with assurance thatthe rubber lwill not flow therearound, and, additionally, it functionsas a very effective metallic sealing or packing material, being deformedappropriately into intimate sealing Contact with the wall of the wellcasing C. The malleable outer ring 51 will not necessarily conform toirregularities and imperfections in the surface of the casing wall.However, despite the fact that the outer malleable ring 51 will notdeform to as great an extent as the lead ring, it is still urgedoutwardly against the casing by high pressure, and the fact that it doesnot deform causes it to act more effectively as a bridge across theannular clearance space 45. The high pressures encountered in the wellbore, in combination with high temperatures therein, will not producebulging of the outer ring 51 into the clearance space 45 that mightproduce its failure, as might occur when lead back-up rings alone areused.

It is, accordingly, apparent that a packing structure has been providedwhich will insure retention of the rubber sealing material at itsintended position whereby its main portion 24 is effective to sealagainst the wall of the well casing C, as well as against the peripheryof the packer body 10. Despite the presence of high pressures andtemperatures in the well casing to which the packing sleeve issubjected, it cannot flow from its intended sealing region through theclearance spaces 45 existing between the well casing C and the upper andlower expanders or abutments 13, 19.

The inventor claims;

l. In a packing structure: a non-metallic packing adapted to engage andseal against a companion member; abutment means adjacent said packingand adapted to provide a clearance space with the companion member; apliant, inelastic deformable annulus adjacent said abutment means andengaging said packing to be forced by said packing against the companionmember to bridge the clearance space and prevent passage of the packingthereinto; and a pliant, inelastic malleable annulus between andengageable with said abutment means and deformable annulus to be forcedby said deformable annulus against the companion member to bridge theclearance space and It will be exprevent passage of the deformableannulus thereinto; said malleable lannulus being substantially 'lessdeformable than said deformable annulus.

2. In a packing structure: a non-metallic packing adapted to engage andseal against a confining enclosure; abutment means adjacent said packingand adapted to provide a clearance space with the enclosure; a pliant,inelastic deformable annulus adjacent said abutment means and engagingsaid packing to be expanded laterally outward by said packing againstthe enclosure to bridge the clearance space and prevent passage of thepacking thereinto; and a pliant, inelastic malleable annulus between andengageable with said abutment means and deformable annulus to beexpanded and stretched laterally outward by said deformable annulus intoa malleable annulus of increased radial width against the enclosure tobridge the clearance space and prevent passage of the deformable annulusthereinto; said malleable annulus being substantially less deformablethan said deformable. annulus.

3. In a packing structure: a non-metallic packing adapted to engage andseal against a companion member; abutment means adjacent said packingand adapted to provide a clearance space with the companion member; apliant, inelastic deformable annulus adjacent said abutment means andhaving an inclined surface engaging a companion inclined surface on saidpacking to be forced by said packing laterally against the companionmember to bridge the clearance space and prevent passage of the packingthereinto when said packing moves toward said abutment means; and apliant, inelastic malleable annulus between said abutment means anddeformable annulus, said malleable annulus and deformable annulus havingcoengaging inclined surfaces to cause said deformable annulus to forcesaid malleable annulus laterally against the companion member to bridgethe clearance space and prevent passage of the deformable annulusthereinto; said malleableannulus being substantially less deformablethan said deformable annulus.

4. In a packing structure: a non-metallic packing adapted to engage andseal against a confining enclosure; abutment means adjacent said packingand adapted to provide a clearance space with the enclosure; a pliant,inelastic deformable annulus adjacent said abutment means, said annulusand packing having coengaging Surfaces inclined outwardly in a directionleading away from said abutment means to cause said packing to forcesaid deformable annulus laterally outward against the enclosure tobridge the clearance space and prevent passage of the packing thereinto;and a pliant, inelastic malleable annulus between and engageable withsaid abutment means and deformable annulus, said deformable annulus andmalleable annulus having coengaging surfaces inclined in the samegeneral direction as said other coengaging surfaces in order that saiddeformable annulus will force and stretch said malleable annuluslaterally outward into a malleable annulus of increased radial width andagainst the enclosure to bridge the clearance space and prevent passageof the deformable annulus thereinto; said malleable annulus beingsubstantially less deformable than said deformable annulus.

5. In a packing structure for a well packer: a nonmetallic packingadapted to engage the wall of a well casing; abutment means adjacentsaid packing and adapted to provide a clearance space with the casing;said packing being provided with a circumferential recess adjacent saidabutment means to provide a groove between said packing and saidabutment means; a pliant, inelastic deformable annulus in said grooveencircling and embracing said packing to prevent its passage into theclearance space; and a pliant, inelastic malleable annulus in saidgroove between and engageable with said abutment means and deformableannulus to be forced and stretched by said deformable annulus into amalleable annulus of increased radial Width laterally against the casingto 7 bridge the clearance space and prevent passage of the deformableannulus thereinto; said malleable annulus being substantially lessdeformable than said deformable annulus.

6. In a packing structure as defined in claim 1; v vherein saiddeformable annulus is a lead member and said malleable annulus is aferrous member.

7. In a packing structure as defined in claim 5; wherein said deformableannulus is a lead member and said malleable annulus is a ferrous member.

8. In a packing structure as defined in claim 1; wherein said deformableannulus is a lead member and said malleable annulus is an aluminummember. v

9. In a packing structure as defined in claim 5; wherein said deformableannulus is a lead member and said malleable annulus is an aluminummember.

l0. In a packing structure: a non-metallic packing adapted to engage andseal against a companion member; abutment means adjacent said packingand adapted to provide a clearance space with the companion member; apliant, inelastic deformable annulus adjacent said abutment means andengaging said packing to be forced by said packing against saidcompanion member to bridge the clearance space and prevent passage ofthe packing thereinto; and a pliant, inelastic malleable annulus betweensaid abutment means and deformable annulus, said malleable annulusengaging said deformable annulus and having one of its peripheralportions only initially engaging said abutment means, whereby saiddeformable annulus pivots said malleable annulus about said abutmentmeans into full engagement with said abutment means and against thecompanion member to bridge the clearance space and prevent passage ofthe deformable annulus thereinto; said malleable annulus beingsubstantially less deformable than said deformable annulus.

ll. In a packing structure: a non-metallic packing adapted to engage andseal against a companion member; abutment means adjacent said packingand adapted to provide a clearance space with the companion member; apliant, inelastic deformable annulus adjacent said abutment means andengaging said packing to be forced by said packing against the companionmember to bridge the clearance space and prevent passage of the packingthereinto; and a pliant, inelastic thin frusto-conical malleable annulusbetween said abutment means and deformable annulus, said thin annulusengaging said deformable annulus and having one of its peripheralportions only initially engaging said abutment means, whereby saiddeformable annulus pivots said thin annulus about said abutment meansinto full engagement with said abutment means and against the companionmember to bridge the clearance space and prevent passage of thedeformable annulus thereinto; said thin annulus being substantially lessdeformable than said deformable annulus.

12. In a packing structure: a non-metallic packing adapted to engage andseal against a confining enclosure; abutment means adjacent said packingand adapted to provide a clearance space with the enclosure; a pliant,inelastic deformable annulus adjacent said abutment means and engagingsaid packing to be expanded outwardly by said packing against theenclosure to bridge the clearance space and prevent passage of thepacking thereinto; and a pliant, inelastic malleable annulus betweensaid abutment means and deformable annulus, said malleable annulusengaging said deformable annulus and having its inner peripheral portiononly initially engaging said abutment means, whereby said deformableannulus pivots said malleable annulus about said abutment means andstretches it into full engagement with said abutment means and againstthe confining enclosure to bridge the clearance space and preventpassage of the deformable annulus thereinto; said malleable annulusbeing substantially less deformable than said deformable annulus.

13. In a packing structure: a non-metallic packing adapted to engage andseal against a confining enclosure; abutment means adjacent said packingand adapted to provide a clearance space with the enclosure; a pliant,inelastic deformable annulus adjacent said abutment means and engagingsaid packing to be expanded outwardly by said packing against theenclosure to bridge the clearance space and prevent passage of thepacking thereinto; and a pliant, inelastic thin frusto-conical malleableannulus between said abutment means and deformable annulus, saidmalleable annulus engaging said deformable annulus and having its innerperipheral portion only initially engaging said abutment means, wherebysaid deformable annulus pivots said malleable annulus about saidabutment means and stretches said malleable annulus into full engagementwith said abutment means and against the confining enclosure to bridgethe clearance space to prevent passage of the deformable annulusthereinto; said malleable annulus being substantially less deformablethan said deformable annulus.

References Cited in the file of this patent UNITED STATES PATENTS2,695,068 Baker et al. Nov. 23, 1954

